The present invention relates generally to co-axial cable connectors, and more particularly to such connectors used with hard-line co-axial cables.
Co-axial cable is a typical transmission medium used in communications networks, such as a CATV network. The cables comprising the transmission portion of the network are typically of the xe2x80x9chard-linexe2x80x9d type, while those used to distribute the signals into residences and businesses are typically xe2x80x9cdropxe2x80x9d connectors. The principal difference between hard-line and drop cables, apart from the size of the cables, is that the hard-line cables include a rigid or semi-rigid outer cable (typically covered with a weather protective jacket) that effectively prevents radiation leaking and protects the inner conductor and dielectric, while the drop cables include a relatively flexible outer conductor, typically braided, that permits their bending around obstacles between the transition or junction box and the location of the device to which the signal is being carried, i.e., a television, computer, and the like. Drop cables are less effective than hard-line cables at preventing radiation leakage. Hard-line conductors, by contrast, generally span considerable distances along relatively straight paths, thereby greatly reducing the need for a cable""s flexibility. Due to the differences in size, material composition, and performance characteristics of hard-line and drop cables, there are different technical considerations involved in the design of the connectors used with these types of cables.
In constructing and maintaining a network, such as a CATV network, the transmission cables are often interconnected to electrical equipment that conditions the signal being transmitted. The electrical equipment is typically housed in a box that may be located outside on a pole, or the like, or underground that is accessible through a cover. In either event, the boxes have standard ports to which the transmission cables may be connected. In order to maintain the electrical integrity of the signal, it is critical that the transmission cable be securely interconnected to the port, and without disrupting the ground connection of the cable. This requires a skilled technician to effect the interconnection.
A typical type of interconnect device used to connect a transmission cable to an equipment port is of the threaded type. The technician must prepare the cable in the standard manner, i.e., stripping the various layers of the cable to their predetermined distances and furrowing out the dielectric material over a predetermined distance in order to bottom out the inner conductor until it is seized by the conductive pin that will carry the signal through the port, and use a wrench to provide torque that will radially compress and seal portions of the connector into the outer jacket of the transmission cable. Such types of connector rely heavily on the skill of the technician in applying the proper amount of torque to effect the connections, thereby making reliability of signal integrity a concern.
In addition to the need for a skilled technician in effecting the connection between the transmission cable and the equipment port, such threaded connectors also require that the transmission cable be separated from the connector the equipment housed in the box needs to be serviced or maintained. It also is difficult to fit a wrench into the space provided by many equipment ports, thereby making the technician""s job that uses threaded connectors even more difficult.
Another type of standard connector used with transmission cables are of the crimping type. With crimp connectors, the technician uses a crimping tool that radially surrounds the connector after the cable has been bottomed out therein, and radially crimps the connector body into engagement with the cable""s outer jacket. While such connectors eliminate the difficulties associated with the threaded connectors, the crimping action often produces inconsistent electrical connection between the connector and the cable, is less effective at preventing moisture migration, and also degrades the cable""s outer conductor, thereby creating signal losses that ultimately reduce the quality of the signal being transmitted.
A compression type connector usable on hard-line cables is disclosed in U.S. Pat. No. 6,331,123. Compression connectors utilize a compression member that is axially slidable into the connector body for radially displacing connecting and sealing members into engagement with the hard-line cable""s outer conductor. A compression tool that slides the compression body into the connector is utilized by the technician to effect the connection, and due to the physical constraints of the compression member and connector body, it is impossible for the technician to use too much force to effect the interconnection. Thus, compression connectors eliminate the assembly drawbacks associated with threaded, and to some degree, crimp type connectors.
It is a principal object and advantage of the present invention to provide a compression type connector for use on hard-line cables.
It is another object and advantage of the present invention to provide a compression type connector that reliably effects interconnection between a hard-line cable and an equipment port.
It is an additional object and advantage of the present invention that reduces technician errors associated with connecting a hard-line cable to an equipment port.
It is a further object and advantage of the present invention to provide a compression type connector for use with hard-line cables that may be inexpensively manufactured with a minimum of waste material.
Other objects and advantages of the present invention will in part be obvious, and in part appear hereinafter.
In accordance with the foregoing objects and advantages, the present invention provides a connector used to interconnect a hard-line co-axial cable to an equipment port. The connector of the present invention essentially comprises a main connector body in which the various connecting and sealing members are housed, and a compression body attached to the connector body for axial, sliding movement between first and second terminal positions relative to the connector body. The port side (also referred to herein as the xe2x80x9cproximalxe2x80x9d end) of the connector includes a conductive pin extending axially outwardly therefrom that is adapted to be inserted into the port provided in the equipment box, and an axially extending bore is formed through the distal end (cable side) of the connector and compression bodies for receiving the central conductor of the hard-line cable therein. A collet electrically connected to the conductive pin seizes the central conductor when it is fully inserted through the axial bore, thereby electrically interconnecting the conductor to the conductive pin that ultimately carries the signal to/from the equipment mounted in the box. A nut is rotatably attached to the proximal end of the connector body and serves to connect the connector body to the equipment port.
After preparing the cable using industry standard preparation tools, the central conductor is fully inserted in the axial bore, the outer conductor of the hard-line cable is positioned annularly between a mandrel that is housed within the connector body and various clamping and sealing members. An industry standard compression tool may then be used by a technician to axially slide the compression body into the connector body. As the compression body slides into to the connector body its ramped, leading face engages a correspondingly ramped surface of a clamping and sealing member. The co-acting ramped surfaces cause the clamping and sealing member to deflect radially inwardly until it contacts the outwardly facing surface of the outer conductor (and possibly a potion of the jacket coating the outer conductor).
The proximal end of the compression body then engages an RF seal driver (that may be an integral part of the clamping and sealing member), and drives it axially within the connector body. As the RF seal driver slides axially in the connector body (as a result of being pushed by the compression body), its proximal end surface engages the distal end surface of the RF seal and drives the RF seal axially. The RF seal includes a portion of its outwardly facing surface that is ramped, and as it is forced axially, the ramped portion of the RF seal engages a correspondingly ramped surface formed on the inwardly facing surface of the connector body. The ramped surface on the connector body forces the RF seal radially inwardly towards the outwardly facing surface of the hard-line cable""s outer conductor. Upon termination of the axial movement of the compression body, the hard-line cable""s outer conductor is sandwiched between the RF seal and the mandrel, and the jacket coating the outer conductor is sandwiched between the clamping and sealing member and the mandrel.
Alternatively, the proximal end surface of the compression body may serve as the RF seal driver. In this arrangement, the proximal end of the compression body pass entirely over the clamping and sealing member and engages the distal end surface of the RF seal in order to drive it axially. Alternate embodiments of the RF seal are also disclosed, as is connector body having a port side that is offset 90 degrees relative to its cable side.